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Associations between Proprioceptive Neural Pathway Structural Connectivity and Balance in People with Multiple Sclerosis.

Fling BW, Dutta GG, Schlueter H, Cameron MH, Horak FB - Front Hum Neurosci (2014)

Bottom Line: We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC).Conversely, while white matter integrity of the right hemisphere's proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS.These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, School of Medicine, Oregon Health & Science University , Portland, OR , USA ; Portland VA Medical Center , Portland, OR , USA.

ABSTRACT
Mobility and balance impairments are a hallmark of multiple sclerosis (MS), affecting nearly half of patients at presentation and resulting in decreased activity and participation, falls, injuries, and reduced quality of life. A growing body of work suggests that balance impairments in people with mild MS are primarily the result of deficits in proprioception, the ability to determine body position in space in the absence of vision. A better understanding of the pathophysiology of balance disturbances in MS is needed to develop evidence-based rehabilitation approaches. The purpose of the current study was to (1) map the cortical proprioceptive pathway in vivo using diffusion-weighted imaging and (2) assess associations between proprioceptive pathway white matter microstructural integrity and performance on clinical and behavioral balance tasks. We hypothesized that people with MS (PwMS) would have reduced integrity of cerebral proprioceptive pathways, and that reduced white matter microstructure within these tracts would be strongly related to proprioceptive-based balance deficits. We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC). Microstructural integrity of this pathway in the right hemisphere was also strongly associated with proprioceptive-based balance control in PwMS and controls. Conversely, while white matter integrity of the right hemisphere's proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS. These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

No MeSH data available.


Related in: MedlinePlus

Relationship between proprioceptive pathway integrity and proprioceptive-based balance. Poorer integrity of the right hemisphere’s proprioceptive tracts originating/terminating in BA 3a is associated with poorer proprioceptive-based balance control. Two PwMS were unable to complete balance trials with eyes closed, thus their data are visualized as X’s on the figure with their Romberg quotient represented as the maximum value observed in the PwMS group. These two datapoints are not included in the linear regression model. HC: r = 0.47; P < 0.07; PwMS: r = 0.74;P < 0.001.
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Figure 5: Relationship between proprioceptive pathway integrity and proprioceptive-based balance. Poorer integrity of the right hemisphere’s proprioceptive tracts originating/terminating in BA 3a is associated with poorer proprioceptive-based balance control. Two PwMS were unable to complete balance trials with eyes closed, thus their data are visualized as X’s on the figure with their Romberg quotient represented as the maximum value observed in the PwMS group. These two datapoints are not included in the linear regression model. HC: r = 0.47; P < 0.07; PwMS: r = 0.74;P < 0.001.

Mentions: Poorer integrity of the right hemisphere’s cortical proprioceptive pathway (higher RD) was associated with lower Mini-BESTest scores in HC (r = −0.58; P < 0.03; not significant when corrected for multiple comparisons), but not in PwMS (r = −0.31; P < 0.27; Table 2) suggesting that proprioceptive feedback is utilized to a lesser degree in PwMS for overall balance control. Similarly, we report a strong correlation between the Romberg quotient (foam standing) and fiber tract integrity of the right hemisphere’s entire cortical proprioceptive pathway in HC (r = 0.61; P < 0.02), but not in PwMS (r = 0.11). This suggests that in HC, vestibular components of balance may also be related to processing and neural conduction within fiber tracts projecting to/from the primary somatosensory cortex, although this requires further inquiry. Poorer integrity of the right hemisphere’s fiber tracts restricted to BA 3a was significantly associated with poorer proprioceptive-based balance control as assessed by the Romberg quotient derived from the firm-surface conditions in PwMS (r = 0.74, P < 0.001) and to a lesser extent in HC (r = 0.47, P < 0.07; Figure 5). This significant relationship is unaffected in PwMS when removing the individual with the worst balance control and fiber tract microstructure (r = 0.73, P < 0.001), and appear to be further strengthened when considering the two PwMS who were unable to maintain eyes-closed balance also possessed very poor fiber tract microstructure (see Figure 5). These results demonstrate that white matter integrity of pathways transmitting proprioceptive feedback strongly influenced somatosensory-based balance control in HC and, to an even greater extent, PwMS. Finally, no associations were observed between metrics of balance performance and proprioceptive tract integrity within the left hemisphere for either group.


Associations between Proprioceptive Neural Pathway Structural Connectivity and Balance in People with Multiple Sclerosis.

Fling BW, Dutta GG, Schlueter H, Cameron MH, Horak FB - Front Hum Neurosci (2014)

Relationship between proprioceptive pathway integrity and proprioceptive-based balance. Poorer integrity of the right hemisphere’s proprioceptive tracts originating/terminating in BA 3a is associated with poorer proprioceptive-based balance control. Two PwMS were unable to complete balance trials with eyes closed, thus their data are visualized as X’s on the figure with their Romberg quotient represented as the maximum value observed in the PwMS group. These two datapoints are not included in the linear regression model. HC: r = 0.47; P < 0.07; PwMS: r = 0.74;P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4202774&req=5

Figure 5: Relationship between proprioceptive pathway integrity and proprioceptive-based balance. Poorer integrity of the right hemisphere’s proprioceptive tracts originating/terminating in BA 3a is associated with poorer proprioceptive-based balance control. Two PwMS were unable to complete balance trials with eyes closed, thus their data are visualized as X’s on the figure with their Romberg quotient represented as the maximum value observed in the PwMS group. These two datapoints are not included in the linear regression model. HC: r = 0.47; P < 0.07; PwMS: r = 0.74;P < 0.001.
Mentions: Poorer integrity of the right hemisphere’s cortical proprioceptive pathway (higher RD) was associated with lower Mini-BESTest scores in HC (r = −0.58; P < 0.03; not significant when corrected for multiple comparisons), but not in PwMS (r = −0.31; P < 0.27; Table 2) suggesting that proprioceptive feedback is utilized to a lesser degree in PwMS for overall balance control. Similarly, we report a strong correlation between the Romberg quotient (foam standing) and fiber tract integrity of the right hemisphere’s entire cortical proprioceptive pathway in HC (r = 0.61; P < 0.02), but not in PwMS (r = 0.11). This suggests that in HC, vestibular components of balance may also be related to processing and neural conduction within fiber tracts projecting to/from the primary somatosensory cortex, although this requires further inquiry. Poorer integrity of the right hemisphere’s fiber tracts restricted to BA 3a was significantly associated with poorer proprioceptive-based balance control as assessed by the Romberg quotient derived from the firm-surface conditions in PwMS (r = 0.74, P < 0.001) and to a lesser extent in HC (r = 0.47, P < 0.07; Figure 5). This significant relationship is unaffected in PwMS when removing the individual with the worst balance control and fiber tract microstructure (r = 0.73, P < 0.001), and appear to be further strengthened when considering the two PwMS who were unable to maintain eyes-closed balance also possessed very poor fiber tract microstructure (see Figure 5). These results demonstrate that white matter integrity of pathways transmitting proprioceptive feedback strongly influenced somatosensory-based balance control in HC and, to an even greater extent, PwMS. Finally, no associations were observed between metrics of balance performance and proprioceptive tract integrity within the left hemisphere for either group.

Bottom Line: We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC).Conversely, while white matter integrity of the right hemisphere's proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS.These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, School of Medicine, Oregon Health & Science University , Portland, OR , USA ; Portland VA Medical Center , Portland, OR , USA.

ABSTRACT
Mobility and balance impairments are a hallmark of multiple sclerosis (MS), affecting nearly half of patients at presentation and resulting in decreased activity and participation, falls, injuries, and reduced quality of life. A growing body of work suggests that balance impairments in people with mild MS are primarily the result of deficits in proprioception, the ability to determine body position in space in the absence of vision. A better understanding of the pathophysiology of balance disturbances in MS is needed to develop evidence-based rehabilitation approaches. The purpose of the current study was to (1) map the cortical proprioceptive pathway in vivo using diffusion-weighted imaging and (2) assess associations between proprioceptive pathway white matter microstructural integrity and performance on clinical and behavioral balance tasks. We hypothesized that people with MS (PwMS) would have reduced integrity of cerebral proprioceptive pathways, and that reduced white matter microstructure within these tracts would be strongly related to proprioceptive-based balance deficits. We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC). Microstructural integrity of this pathway in the right hemisphere was also strongly associated with proprioceptive-based balance control in PwMS and controls. Conversely, while white matter integrity of the right hemisphere's proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS. These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system.

No MeSH data available.


Related in: MedlinePlus